Thanks David for the explanation. As you can see I already included a workaround: #define extIntSetEnable_gcc_4_3_3_aail_workaround __attribute__((always_inline)) I use it with #if (GCC_VERSION == 40303UL) in my library :) In this case it's clearly better to inline, but the function might be called with variable parameters in other cases, so it would be nice not to force the compiler...
My next question might prompt a RTFM answer in some ppl, but pls resist the urge. Anyone know if this new behavior can be disabled by command line switch? I looked through the options that had something to do with inlining at http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html but did not find how to get the old behavior without always inline attribute. But maybe I just missed it. Thanks Eric but I already know about http://www.nongnu.org/avr-libc/bugs.html and also https://savannah.nongnu.org/bugs/?group=avr-libc , http://gcc.gnu.org/bugzilla/ . But I thought it was indexed by google. The entire point of me writing this mail was that I did not find this reported. (which does not mean it's not, I might just not used the right search phrase) So I guess this should not be reported as a bug, because it would be hard to fix so wouldn't happen anyway Regards, Istvan On Sun, Mar 28, 2010 at 12:15 AM, David Brown <david.br...@hesbynett.no> wrote: > Szikra Istvan wrote: >> >> /** >> Category: miss optimization >> affects: avr-gcc 4.3.3 >> Size optimization inline check generates bigger code >> >> I get this warning: "inlining failed in call to 'extIntSetEnable': >> optimizing for size and code size would grow" >> NO! It would not! >> >> Is this a known bug, or something that should be reported? >> (tried google 'avr optimizing for size and code size would grow' with no >> joy) >> > > The algorithms for estimating code growth size on inlining are not perfect - > it's a very hard problem to solve accurately while keeping a sensible > compile time. So much is done based on the complexity of the inline > candidate by itself, not within the context of where it is used. In cases > like this where constant folding will reduce the inlined function to a few > statements, you should use __attribute__((always_inline)) to force inlining. > Then you'll get the code you want. > > mvh., > > David > > >> See the test case for an example: >> (sorry if it's still a bit much, but I tried to strip everything >> that's not relevant. >> I spent a lot of time on it, and it's a fraction of the original code.) >> In this case NOT inlining generates more then 5 times as much >> instructions than inlining! >> */ >> >> #define extIntSetEnable_gcc_4_3_3_aail_workaround >> //#define extIntSetEnable_gcc_4_3_3_aail_workaround >> __attribute__((always_inline)) >> >> #include <avr/io.h> >> #include <avr/interrupt.h> >> >> #define BIT(x) (0x01 << (x)) >> #define bit_set(p,b) ((p) |= BIT(b)) >> #define bit_clear(p,b) ((p) &= ~BIT(b)) >> //#define bit_write(p,b,c) (c ? bit_set(p,b) : bit_clear(p,b)) >> #define bit_write(p,b,c) if (c) { bit_set(p,b);}else bit_clear(p,b) >> >> static inline >> void extIntSetEnable_gcc_4_3_3_aail_workaround extIntSetEnable(char >> channel, char enabled) >> { >> switch (channel) { /// enable / disable int >> case 0: { >> bit_write(GICR,INT0,enabled); >> } break; >> case 1: { >> bit_write(GICR,INT1,enabled); >> } break; >> case 2: { >> bit_write(GICR,INT2,enabled); >> } break; >> } >> } >> int main (void) >> { >> extIntSetEnable(0,0); >> ///... >> extIntSetEnable(0,1); >> for (;;) >> { >> } >> } >> >> /** >> avr-gcc (GCC) 3.4.6 >> avr-gcc -c -mmcu=atmega16 -I. -gdwarf-2 -DF_CPU=16000000UL >> -DBOOTSIZE=1024 -Os -funsigned-char -funsigned-bitfields >> -fpack-struct -fshort-enums -fno-strict-aliasing -Wall -Winline >> -Wstrict-prototypes -Wa,-adhlns=test_il.lst -ID:/Lib/ -std=gnu99 -MD >> -MP -MF .dep/test_il.o.d test_il.c -o test_il.o >> avr-gcc -mmcu=atmega16 -I. -gdwarf-2 -DF_CPU=16000000UL >> -DBOOTSIZE=1024 -Os -funsigned-char -funsigned-bitfields >> -fpack-struct -fshort-enums -fno-strict-aliasing -Wall -Winline >> -Wstrict-prototypes -Wa,-adhlns=test_il.o -ID:/Lib/ -std=gnu99 -MD -MP >> -MF .dep/test_il.elf.d test_il.o --output test_il.elf >> -Wl,-Map=test_il.map,--cref -lm >> -Wl,--section-start=.bootloader=0x3800 >> Size after: >> .text 184 0 >> >> 00000054 <__ctors_end>: >> 58: cf e5 ldi r28, 0x5F ; 95 >> 5a: d4 e0 ldi r29, 0x04 ; 4 >> 5c: de bf out 0x3e, r29 ; 62 >> 5e: cd bf out 0x3d, r28 ; 61 >> ... >> 0000008e <main>: >> 8e: cf e5 ldi r28, 0x5F ; 95 <<< again? ... gcc >> 3.4.6 has >> it's own faults >> 90: d4 e0 ldi r29, 0x04 ; 4 >> 92: de bf out 0x3e, r29 ; 62 >> 94: cd bf out 0x3d, r28 ; 61 >> >> extIntSetEnable(0,0); >> 96: 8b b7 in r24, 0x3b ; 59 >> 98: 8f 7b andi r24, 0xBF ; 191 >> 9a: 8b bf out 0x3b, r24 ; 59 >> extIntSetEnable(0,1); >> 9c: 8b b7 in r24, 0x3b ; 59 >> 9e: 80 64 ori r24, 0x40 ; 64 >> a0: 8b bf out 0x3b, r24 ; 59 >> >> */ >> >> /** >> avr-gcc (WinAVR 20090313) 4.3.2 >> avr-gcc -c -mmcu=atmega16 -I. -gdwarf-2 -DF_CPU=16000000UL >> -DBOOTSIZE=1024 -Os -funsigned-char -funsigned-bitfields >> -fpack-struct -fshort-enums -fno-strict-aliasing >> -fno-inline-small-functions -save-temps -Wall -Winline >> -Wstrict-prototypes -Wa,-adhlns=test_il.lst -ID:/Lib/ -std=gnu99 -MD >> -MP -MF .dep/test_il.o.d test_il.c -o test_il.o >> avr-gcc -mmcu=atmega16 -I. -gdwarf-2 -DF_CPU=16000000UL >> -DBOOTSIZE=1024 -Os -funsigned-char -funsigned-bitfields >> -fpack-struct -fshort-enums -fno-strict-aliasing >> -fno-inline-small-functions -save-temps -Wall -Winline >> -Wstrict-prototypes -Wa,-adhlns=test_il.o -ID:/Lib/ -std=gnu99 -MD -MP >> -MF .dep/test_il.elf.d test_il.o --output test_il.elf >> -Wl,-Map=test_il.map,--cref -lm >> -Wl,--section-start=.bootloader=0x3800 >> Size after: >> .text 146 0 >> >> 0000006c <main>: >> bit_write(GICR,INT0,enabled); >> 6c: 8b b7 in r24, 0x3b ; 59 >> 6e: 8f 7b andi r24, 0xBF ; 191 >> 70: 8b bf out 0x3b, r24 ; 59 >> >> 72: 8b b7 in r24, 0x3b ; 59 >> 74: 80 64 ori r24, 0x40 ; 64 >> 76: 8b bf out 0x3b, r24 ; 59 >> >> */ >> >> /** >> avr-gcc (WinAVR 20100110) 4.3.3 >> avr-gcc -c -mmcu=atmega16 -I. -gdwarf-2 -DF_CPU=16000000UL >> -DBOOTSIZE=1024 -Os -funsigned-char -funsigned-bitfields >> -fpack-struct -fshort-enums -fno-strict-aliasing >> -fno-inline-small-functions -save-temps -Wall -Winline >> -Wstrict-prototypes -Wa,-adhlns=test_il.lst -ID:/Lib/ -std=gnu99 -MD >> -MP -MF .dep/test_il.o.d test_il.c -o test_il.o >> test_il.c: In function 'main': >> test_il.c:32: warning: inlining failed in call to 'extIntSetEnable': >> optimizing for size and code size would grow >> test_il.c:49: warning: called from here >> test_il.c:32: warning: inlining failed in call to 'extIntSetEnable': >> optimizing for size and code size would grow >> test_il.c:54: warning: called from here >> avr-gcc -mmcu=atmega16 -I. -gdwarf-2 -DF_CPU=16000000UL >> -DBOOTSIZE=1024 -Os -funsigned-char -funsigned-bitfields >> -fpack-struct -fshort-enums -fno-strict-aliasing >> -fno-inline-small-functions -save-temps -Wall -Winline >> -Wstrict-prototypes -Wa,-adhlns=test_il.o -ID:/Lib/ -std=gnu99 -MD -MP >> -MF .dep/test_il.elf.d test_il.o --output test_il.elf >> -Wl,-Map=test_il.map,--cref -lm >> -Wl,--section-start=.bootloader=0x3800 >> Size after: >> .text 216 0 >> >> >> 0000006c <extIntSetEnable>: >> switch (channel) { /// enable / disable int >> 6c: 81 30 cpi r24, 0x01 ; 1 >> 6e: 69 f0 breq .+26 ; 0x8a >> <extIntSetEnable+0x1e> >> 70: 81 30 cpi r24, 0x01 ; 1 >> 72: 18 f0 brcs .+6 ; 0x7a >> <extIntSetEnable+0xe> >> 74: 82 30 cpi r24, 0x02 ; 2 >> 76: e1 f4 brne .+56 ; 0xb0 >> <extIntSetEnable+0x44> >> 78: 10 c0 rjmp .+32 ; 0x9a >> <extIntSetEnable+0x2e> >> case 0: { >> bit_write(GICR,INT0,enabled); >> 7a: 66 23 and r22, r22 >> 7c: 19 f0 breq .+6 ; 0x84 >> <extIntSetEnable+0x18> >> 7e: 8b b7 in r24, 0x3b ; 59 >> 80: 80 64 ori r24, 0x40 ; 64 >> 82: 0f c0 rjmp .+30 ; 0xa2 >> <extIntSetEnable+0x36> >> 84: 8b b7 in r24, 0x3b ; 59 >> 86: 8f 7b andi r24, 0xBF ; 191 >> 88: 0c c0 rjmp .+24 ; 0xa2 >> <extIntSetEnable+0x36> >> } break; >> case 1: { >> bit_write(GICR,INT1,enabled); >> 8a: 66 23 and r22, r22 >> 8c: 19 f0 breq .+6 ; 0x94 >> <extIntSetEnable+0x28> >> 8e: 8b b7 in r24, 0x3b ; 59 >> 90: 80 68 ori r24, 0x80 ; 128 >> 92: 07 c0 rjmp .+14 ; 0xa2 >> <extIntSetEnable+0x36> >> 94: 8b b7 in r24, 0x3b ; 59 >> 96: 8f 77 andi r24, 0x7F ; 127 >> 98: 04 c0 rjmp .+8 ; 0xa2 >> <extIntSetEnable+0x36> >> } break; >> case 2: { >> bit_write(GICR,INT2,enabled); >> 9a: 66 23 and r22, r22 >> 9c: 21 f0 breq .+8 ; 0xa6 >> <extIntSetEnable+0x3a> >> 9e: 8b b7 in r24, 0x3b ; 59 >> a0: 80 62 ori r24, 0x20 ; 32 >> a2: 8b bf out 0x3b, r24 ; 59 >> a4: 08 95 ret >> a6: 8b b7 in r24, 0x3b ; 59 >> a8: 8f 7d andi r24, 0xDF ; 223 >> aa: 8b bf out 0x3b, r24 ; 59 >> ac: 08 95 ret >> >> 000000ae <main>: >> extIntSetEnable(0,0); >> ae: 80 e0 ldi r24, 0x00 ; 0 >> b0: 60 e0 ldi r22, 0x00 ; 0 >> b2: 0e 94 36 00 call 0x6c ; 0x6c <extIntSetEnable> >> extIntSetEnable(0,1); >> b6: 80 e0 ldi r24, 0x00 ; 0 >> b8: 61 e0 ldi r22, 0x01 ; 1 >> ba: 0e 94 36 00 call 0x6c ; 0x6c <extIntSetEnable> >> >> */ >> >> SIGNAL(SIG_INTERRUPT0) >> { >> } >> _______________________________________________ AVR-GCC-list mailing list AVR-GCC-list@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-gcc-list
